"USA Cycling will not speculate on the reasoning behind their requests and will not have further comment on this topic; any questions related to their decision should be directed to the individual athletes," it released via a statement.

Leipheimer, 38, may have been a consideration for the one time trial position on the US team, having won a bronze medal in the event at the 2008 Games in Beijing. However after being hit by a car while training in April, Leipheimer admitted he was an unlikely starter.

Hincapie, also 38, has represented his country for the last five Olympic Games – from Barcelona in 1992 through to Beijing in 2008. Just last week, the three-time national road champion announced his retirement at the end of the season. He talked to Cyclingnews last year about the prospect of a sixth Olympics.

"It would be nice; I've done five of them. To do a sixth Olympics would be pretty cool. It's pretty crazy actually to think of that," admitting at the time that ending his career at the Games had not entered his thinking.

In May 2011, Hincapie was alleged to have given evidence to a grand jury in the Jeff Novitzky-led federal investigation into alleged doping practices in American cycling. Unidentified sources claimed that Hincapie told the grand jury that he and Armstrong supplied each other with EPO and also discussed the use of testosterone. Hincapie later denied giving such evidence.

"I can confirm to you that I never spoke with '60 Minutes,' he said via a statement through his attorney. "I have no idea where they got their information. As I've said in the past, I continue to be disappointed that people are talking about the past in cycling instead of the future. As for the substance of anything in the '60 Minutes' story, I cannot comment on anything relating to the ongoing investigation."

Vande Velde missed the chance to compete in Beijing having been passed over in favour of Leipheimer and so the Garmin – Barracuda rider admitted that London was one of his goals for the 2012 season.

"I want to go to the Olympics really bad," he told Cyclingnews earlier this year. "I don't see myself going to Rio – I don't want to go to Rio... I want to come out of the Tour de France really well and I know that in the past that I always have. So the road race coming five days after the Tour de France and the Champs Elysees, I know I can do a good race."

Zabriskie, five time and reigning national time trial champion was seemingly involved in a tight two-man battle for the sole time trial spot on the team. Selectors announced yesterday that 21-year-old Taylor Phinney was their pick.

Speaking after the Tour of California where he dominated the Bakersfield time trial, Zabriskie said he was motivated to perform in order to gain an Olympic bid, and said the selection committee should "take who [they] think is the best. It's pretty simple."

On Wednesday, USADA formally charged Armstrong with doping with the use of evidence gathered in investigation of potential doping on the United States Postal Service (USPS) (1996-2004), Discovery Channel (2005-2007), Astana (2009) and RadioShack (2010) cycling teams. Johan Bruyneel, Dr. Pedro Celaye, Dr. Luis Garcia del Moral, Dr. Michele Ferrari, and Mr. Pepe Marti are also accused of a variety of doping violations, from the administration of doping products, trafficking, assisting and abetting and covering up.

USADA names 10 witnesses to the alleged conduct, made up of cyclists and cycling team employees, but their identities remain secret.